CN1902973A - Method of synchronizing broadcast streams in multiple soft handoff sectors - Google Patents

Abstract

Transmission of broadcast streams in multiple sectors is synchronized based on time stamps or sequence numbers in data packets received at the base station. The base stations use the time stamps to calculate a frame transmission start time and start position for the data packets. The base station monitors the packet latency of data within its buffer based on the time stamp in the data packets and initiates a resynchronization procedure if the packet latency exceeds predetermined bounds.

Description

In a plurality of soft handoff sectors, make the synchronous method of broadcasting stream

Related application

[0001] priority of 60/611489 these U.S. Provisional Patent Application of submitting in 20,60/527861 and 2004 on September of submitting in 8,60/517739,2003 on December requiring to submit on November 5th, 2003 of the application is attached to it herein by reference.

Background of invention

[0002] in general, the present invention relates to be used for the broadcasting and the multicast service of cordless communication network, and more particularly, relate to the autonomous soft handover that when receiving broadcasting stream, between the base station, carries out by travelling carriage.

[0003] third generation (3G) cordless communication network provides to packet data network, as the wireless access of internet for the mobile subscriber.The many internets application and service that once was used for fixing the user of terminal only becomes via cordless communication network now and can be used for the mobile subscriber.Service such as real-time streaming video and music and on-line interaction recreation just offers several examples in mobile subscriber's the service via wireless network now.Demand to this class service requires the standardisation bodies exploitation that the 3G standard of high speed data transfers can be provided by the radio interface between Access Network and the mobile subscriber.

[0004] broadcast (BCMCS) provides by the ability of shared forward link channel while to a plurality of user's transfers media content.The BCMCS stream that is called broadcasting stream herein transmits with fixed rate and with firm power.Travelling carriage switches independently to be carried out by travelling carriage.In order to improve systematic function, the autonomous soft handover between the sector in the cordless communication network of the broadcasting stream that hope support transmission is identical.The soft handover requirement that receives the travelling carriage of broadcasting stream is synchronous in time from the transmission of the broadcasting stream of each sector.

Summary of the invention

[0005] the invention provides a kind of transmission synchronizing method that during soft handover, makes from the broadcasting stream of two or more sectors.In an example embodiment of the present invention, receive the packet that comprises broadcasting stream in the base station.Each packet comprises the markers that can be applied at service node by grouped data.The frame transmission start time of the initial air interface frame of each packet is calculated in the base station according to markers and packet.The frame transmission start time of being calculated then is used for making transmission and other base station synchronization of air interface frame.

[0006], provide automatically again synchronizing process to overflow and underflow to prevent buffer in another aspect of the present invention.Base station monitors transmits the bag stand-by period of the packet in the buffer.When the bag stand-by period of packet was in outside the predetermined minimum and maximum bag stand-by period thresholding, synchronizing process was again carried out in the base station.Exceed under the situation of predetermined maximum bag stand-by period thresholding in the bag stand-by period, the base station abandons the selected data bag from its buffer, and recomputates the frame transmission start time of any remainder data bag.Under the situation of the bag stand-by period of packet less than predetermined parcel stand-by period thresholding, the base station postpones the transmission of selected data bag, and recomputates the frame transmission start time of institute's delayed data bag.

Brief description

[0007] Fig. 1 is the sketch of basis based on the cordless communication network of an example embodiment of cdma2000 standard.

[0008] Fig. 2 is the sketch of basis based on the radio access network of one embodiment of the present of invention of cdma200 standard.

[0009] Fig. 3 is a call flow diagram, and the broadcast parameter coordination process of basis based on one embodiment of the present of invention of distributed control is described.

[0010] Fig. 4 is the block diagram that is configured to realize the exemplary base station of broadcast parameter coordination process shown in Figure 3.

[0011] Fig. 5 is a flow chart, and the demonstration programme that is moved by the base station of initiating broadcast parameter coordination process as shown in Figure 3 is described.

[0012] Fig. 6 is a flow chart, and the demonstration programme that is moved by the base station of response broadcast parameter coordination request as shown in Figure 3 is described.

[0013] Fig. 7 is a call flow diagram, illustrates according to the alternative broadcast parameter coordination process that adopts a central controlled embodiment.

[0014] Fig. 8 is a sketch, and the demonstration methods to the broadcast stream bag is described.

[0015] Fig. 9 is a block diagram, and data and the signal path that is respectively applied for broadcasting stream and relevant signaling according to an embodiment of the invention is described.

[0016] Figure 10 is a block diagram, and the data and the signal path that are respectively applied for broadcasting stream and relevant signaling according to an alternative of the present invention are described.

[0017] Figure 11 is a call flow diagram, and alternative broadcast parameter coordination process according to an embodiment of the invention is described.

The detailed description of invention

[0018] Fig. 1 explanation provides the logic entity of the exemplary wireless communication network 10 of broadcast (BCMCS) to travelling carriage 100.Cordless communication network 10 may be the cordless communication network of any kind, for example cdma network, WCDMA network, GSM/GPRS network, EDGE network or UMTS network.Fig. 1 explanation is according to the network 10 of cdma2000 standard configuration.Cordless communication network 10 comprises packet switched core network 20 and radio access network (RAN) 40.Core net 20 is connected to one or more external packet data networks 16, as the internet, perhaps be connected to other cordless communication network.RAN 30 is connected to core net 20, and is used as the access point of travelling carriage 100.

[0019] core net 20 comprise grouped data service node (PDSN) 22, broadcasting in service node (BSN) 24, BCMCS controller 26, BCMCS content server (BCMCS-CS) 28 and authentication, authorize and the server that accounts (AAA) 30.Core net 20 also can comprise BCMCS content provider (BCMCS-CP) 32, but person of skill in the art will appreciate that BCMCS-CP 32 can be positioned at the outside of core net 20.

[0020] PDSN 22 be connected to external packet data network (PDN) 60, as the internet, and support to being connected with PPP from travelling carriage 100.It adds and from wherein deleting IP stream to RAN 40, and route bag between packet data network 16 and the RAN 40 externally.The BSN 24 that can be attached among the PDSN 22 is connected to BCMCS-CS 28, and supports extremely and from the BCMCS of travelling carriage 100 to flow.It is to RAN 30 interpolations with from wherein deleting BCMCS stream.The function of BSN 24 can be attached among the PDSN 22 when needed.

[0021] BCMCS controller 26 is in charge of the BCMCS session information and is provided BCMCS session information to BSN 24, BCMCS-CS 28, RAN 40 and travelling carriage 100.BCMCS-CS 28 makes the BCMCS content can be used for the logic entity of travelling carriage 100.BCMCS-CS 28 is content source not necessarily, but can be from content provider's received content.It can store and transmit the content from the content provider, perhaps can merge the content from a plurality of content providers.If use to encrypt, but BCMCS-CS 28 convection current content-encrypts then.But it is the reformatting content also, so that pass to travelling carriage 100.

[0022] AAA 30 is responsible for authentication, the function of authorizing and account.Its access subscribers profiles database (not shown) is with acquired information from user's subscription profiles, and user's subscription profiles can be sent to BCMC-CS 28.

[0023] content provider 32 is sources of the entrained content of BCMCS stream.Broadcasted content can comprise real-time broadcasting or broadcast program, for example video request program of having stored.BCMCS-CP 32 may be in the home network of travelling carriage or outside PDN, as the server in service network in the internet.If content provider 32 is in outside the network, then the content provider is the broadcasted content subpackage, so that pass to BCMCS-CS 28 in the core net 20 by IP network, it makes content can be used for travelling carriage 100 in the cordless communication network 10.

[0024] RAN 40 comprises Packet Control Function (PCF) 42, base station controller (BSC) 44 and one or more radio base station (RBS) 46.The major function of PCF 32 is to set up, safeguard and be terminated to being connected of PDSN 22.Radio resource in BSC 44 their respective coverage areas of management.RBS 36 communicates by air interface and travelling carriage 100.Be that a kind of BCMCS demonstration air interface specification of service that is used to provide is provided in third generation collaborative project 2 (3GPP2) standard of " CDMA two-forty broadcasting-multicast packet data air interface standard; version 1.0 " (in February, 2004) (BCMCS air interface specification) at title, it is incorporated herein by reference.BSC 44 can manage an above RBS 46.In the cdma2000 network, BSC 44 and RBS 46 comprise base station 50 (Fig. 4), are described in more detail below.In the cdma2000 network, single BSC 44 can comprise the part of a plurality of base stations 50.In other network architecture, comprise that the networking component of base station 50 may be different, but overall function will be same or similar based on other standard.

[0025] the BCMCS service provides simultaneously and sends the ability that this paper is called the identical information stream of BCMCS stream or broadcasting stream to a plurality of users.BCMCS stream is called the BCMCS data flow again.The BCMCS service can be used for the video streaming uses, and is used for providing the video conference function to travelling carriage 100.Typical video streaming is used and is comprised Live Audio and video request program (VOD).In Fig. 1, the content of BCMCS stream is received from BCMCS-CP 32 by BCMCS-CS 28.A plurality of travelling carriages 100 that BCMCS stream flows to the different sectors that may be in cordless communication network 10 from BCMCS-CS 28.The breakout of BCMCS stream in network 10 is replicated, so that make stream can be used for different sectors.For example, PCF 44 can divide BCMCS stream so that pass to two or more BSC 44, and BSC 44 can divide BCMCS stream again so that pass to two or more RBS 46.One or more RBS 36 flow to travelling carriage 100 broadcasting BCMCS by Forward Broadcast Channel.BCH can comprise the plurality of sub channel that is called broadcast logical channel herein.BCMCS stream carries on broadcast logical channel.Each broadcast logical channel can be carried one or more BCMCS streams.In order to allow travelling carriage 100 successfully find and monitor broadcasted content, the parameter that various broadcasting are relevant need send to mobile receiver by air interface.Network is broadcasted these parameters with the form of broadcast overhead messages by BCH.Broadcast overhead messages comprises the logic that is used for each BCMCS stream and shines upon and other parameter to physical channel, so that make travelling carriage 100 can successfully receive BCMCS stream.

[0026] though not essential to the present invention,, the description of BCMCS service may be useful for understanding the present invention.By title is that a plurality of processes of describing in the 3GPP2 standard of " broadcasting and multicast service framework X.P0019, Rev.0.1.4 " (on March 15th, 2004) (framework) realize the reception that BCMCS serves.Basic process comprises that service discovery/notice, content subscription, content information obtain, content availability is determined, BCMCS registers, the reception of content and BCMCS un-register.Network 10 provides one or more mechanism, the notice that makes the user can ask the BCMCS service or obtain serving about available BCMCS.BCMCS-CS 28 can be used as with travelling carriage 100 in the server that communicates of client application.Client application can be to BCMCS-CS 28 request BCMCS information on services, and perhaps BCMCS-CS 28 can send the unsolicited notice about the BCMCS service.Other service discovery/informing mechanism comprises the notice via SMS and WAP.Whatsoever mechanism is used for service discovery/notice, and the information relevant with timetable with the BCMCS content is provided for travelling carriage 100.Service discovery/informing mechanism provide about information obtain the essential information of required service, as content name and zero-time.

[0027] user subscribes the BCMCS content, and selects him to want the content that receives.Content subscription can be carried out before service discovery/notice or afterwards.User's subscription information is stored in subscriber's profile.In order to receive selected content, travelling carriage 100 communicates with BCMCS controller 26, so that obtain the session information with selected BCMCS relevance.This process is called content information and obtains.Session information comprises such as the stream processing of the BCMCS flow identifier of sign BCMCS stream, for example header decompression will and/or head deletion and the information employed transmission and the application protocol.

[0028] the content availability deterministic process makes travelling carriage 100 can determine the availability of particular B CMCS stream.Can in Overhead Message, transmit availability information for content at service RBS 46 to MS.If travelling carriage 100 can't find availability information for content from Overhead Message, then travelling carriage 100 can ask to expect that BCMCS flows by carrying out the BCMCS register requirement.

[0029] travelling carriage 100 adopts the BCMCS registration process to ask the transmission of BCMCS stream.In the cdma200 network, the BCMCS register requirement is sent at service RBS36 by Random Access Channel (RACH) or enhancing Random Access Channel (REACH) by travelling carriage 100.If do not set up the bearer path between BCMCS-CS 28 and the RBS 46, then the RBS 46 with BCMCS-CS 28 compounding practices will set up bearer path.In case travelling carriage 100 begins to receive BCMCS stream, then RBS 46 can require travelling carriage 100 regularly to re-register.When not having travelling carriage 100 to receive stream, registration regularly allows the RBS 46 BCMCS stream of going off the air.

[0030] travelling carriage 100 can be carried out BCMCS un-register process, so that notice RBS 46 no longer monitors the situation of BCMCS stream about travelling carriage 100.Expire if be used for the un-register timer of travelling carriage 100, then un-register also can be via overtime on the RBS 46 and be taken place.

[0031] broadcast channel (BCH) that is used for by air interface transmission BCMCS stream can be shared channel or dedicated channel.In general, BCH will have forward link and not have reverse link.In cdma2000, broadcast channel can comprise one or more forward complement channels (F-SCH).BCH also can carry by the forward packet data channel F-PDCH that shares among Packet Data Channel, for example cdma2000.The BCH carrying comprises the bag of the BCMCS content that is produced by BCMCS-CS 28.BCH also can carry the forward link signaling message.Each BCMCS stream is related with the identifier that is called BCMCS stream ID.

[0032] travelling carriage 100 of the broadcasting of the sub-district of the RBS 46 in receiving automatic network 10 or sector stream is when its active set adds another sub-district of another RBS 46 that is just serving identical broadcasts stream or sector, and travelling carriage 100 is carried out autonomous soft handover.Fig. 2 illustrates the travelling carriage 100 between transfer period, and the more details of RAN 30 are provided.Fig. 2 illustrates three RBS46, and the covering in the geographic area that is called sub-district 12 respectively is provided.Sub-district 12 is expressed as hexagonal area, and called after sub-district C1, C2 and C3.Each sub-district 12 is divided into three sectors and disturbs to reduce.Called after sector, sector S1, S2 and S3 in each sub-district 12.Two BSC 44 of called after BSC1 and BSC2 are described.First base station BS 1 of the covering that provides among the C1 of sub-district is provided for RBS1 and BSC1.Second base station BS 2 of the covering that provides among the C2 of sub-district is provided for RBS2 and BSC1.The 3rd base station BS 3 of the covering that provides among the C3 of sub-district is provided for RBS3 and BSC2.BSC1 leads (sidehaul) link with BSC2 by the side that is called the A3/A7 interface in the IS-2001 standard and is connected.The A3 interface transmits customer service between BSC 44, and the A7 interface transmits signaling between BSC 44.

[0033] as shown in Figure 2, the travelling carriage 100 among the C2 of sub-district has entered the borderline region 14 between the sector S3 of the sector S1 of sub-district C2 and sub-district C3.Before entering borderline region, travelling carriage 100 is just receiving the broadcasting stream from BS2.Network 10 travelling carriage 100 in must detection boundaries zones 14, and provide identical broadcasting stream to BS3, so that realize that BS2 is to the switching between the BS3.Network 10 can detect travelling carriage 100 and enter borderline region 14 by the signal quality reporting of monitoring from travelling carriage 100.For example, when travelling carriage 100 is in borderline region 14, the regular Pilot Strength Measurement Message (PPSMM) that returns from travelling carriage 100 etc. will comprise the pilot frequency intensity measuring result for one or more adjacent base stations in the related adjacency service district of control and borderline region 14.Therefore, the received signal intensity that BS2 can detect its pilot tone reduces on travelling carriage 100, and the received signal intensity of BS3 increases.When the travelling carriage 100 in the network 10 detection boundaries zones 14, it provides broadcasting stream to each adjacent base station 50 of the switching that expection is undertaken by travelling carriage 100.

[0034] in a preferred embodiment of the invention, travelling carriage 100 is according to independently switching from pilot frequency intensity measuring result and/or other channel quality statistical information of adjacent base station.In order to improve systematic function, wish the soft handover that support is undertaken by the travelling carriage 100 that receives broadcasting stream, so that realize the soft combination on the travelling carriage 100.When travelling carriage 100 between the sector that service is provided by same base or between the sector in two different base stations that service is provided by identical BSC 44 when mobile, can use traditional soft switching process.Also wish to support to be called the borderline soft handover of the BSC that switches between BSC herein.

[0035] the invention provides can be by the process of 50 realizations of the base station in the network 10, so that the autonomous soft handover that support is carried out on the BSC border by travelling carriage 100.Soft handover requires in the transmission that participates in coordinating between the base station 50 broadcasting stream.BCMCS stream ID is that PDSN 22, base station 50 and travelling carriage 100 are known, and can be used to coordinate broadcasting stream content and broadcast parameter.Need the part of the broadcast parameter of coordination to comprise:

● coding need transmit with the phase same rate with data rate-identical content, need use the same application-level coding on each sector in soft handover.May wish to use more than one coding/compression algorithm to adapt to may time dependent available bandwidth.

● broadcasting stream need be transmitted in frequency-each base station 50 on same frequency.

● Long Code Mask-each base station 50 needs identical Long Code Mask is applied to broadcasting stream.

● framing-have two kinds of framing methods to can be used for the framing of BCMCS-on the PDSN/BSN that adopts HDLC, and the framing on the BSC 44 that adopts the broadcasting frame-forming protocol.

● stream level encryption-base station 50 must coordinate to encrypt.Possible encipherment scheme comprises that link level encryption, application layer are encrypted or they both.Identical encryption key need be used by each base station.

● the security parameter needs of link level encryption-be used for link level encryption are identical, otherwise should forbid link level encryption.Ephemeral keys is from BAK and seed number generation at random.BAK is all identical for all base stations 50.In order to realize encrypting, the seed number need be exchanged at random.The base station should be adopted the same Hash function to be used for short key and be generated, and it produces identical short key in all base stations.

● coding-in cdma2000, Reed-Solomon (RS) external encode only is activated for speed 115200bps Reed-Solomon.When being activated, the beginning of the RS piece of Reed-Solomon coding is essential identical, makes that the calculating of the transmission of information bit and parity check bit is synchronous.

● time synchronized-identical data need be transmitted from common sector in the identical time during soft handover.Transmission should be synchronous in time frame by frame.

● identical frame biasing must be used in frame biasing-each base station 50.

● power bias-travelling carriage 100 carries out soft combination according to the pilot power level that it is understood for the sector to bag.Pilot power level may be different for different sectors.For max ratio combined, business is compared to all sectors with pilot tone preferably should be identical.

● neighborhood tabulation-travelling carriage 100 need obtain about carrying out the notice of the possible set of sectors of soft combination by the broadcast overhead messages of common channel messages transmission, for example IS6001 (1xEV-DO) and the broadcast service parameter message of IS-2001 (1xEV-DV).The base station 50 that participates in soft handover need decide through consultation and will transmit the sector of broadcasting stream that they may be the subclass of the active set of travelling carriage 100.

The part of broadcast parameter listed above may be fixed, and other parts then may be negotiable between participation base station 50.In addition, the above tabulation of broadcast parameter is not to be intended to restriction, and as to above replenishing or substituting of listing, those skilled in the art may find the reason of adding other broadcast parameter.

[0036] in an example embodiment of the present invention, equity or distributed control method are used for coordinating broadcast parameter.Utilize reciprocity method, each base station 50 comprises the broadcast service function 64 (Fig. 4) of the service that the broadcast service that provides support is required, comprising coordinating broadcast parameter with its neighborhood.Broadcast service function 64 on any base station 50 can be initiated the broadcast parameter coordination process.The arbitrator's of broadcast parameter coordination process role is served as in the base station 50 of starting.Three-hand shake is used for coordinating broadcast parameter in greater detail below, and does not have participation or the intervention of PDSN 22.In addition, the broadcast parameter coordination process does not need any signal transmission with travelling carriage 100, but soft handoff sectors is notified travelling carriage 100 after the broadcast parameter coordination process is finished.The tabulation of soft handoff sectors sends to travelling carriage 100 in can be in shared overhead message, as the broadcast service parameter message in broadcast overhead messages in the 1xEV-DO system or the 1xEV-DV system.

[0037] Fig. 3 is a call flow diagram, and the broadcast parameter coordination process that switches between BSC according to an embodiment of the invention is described.In example shown in Figure 3, travelling carriage 100 has moved to two borderline regions 44 between the sector in the BSC area of coverage.In this example, travelling carriage 100 has moved to the borderline region adjacent with BS1, and sends login request message to BS1, and it triggers the broadcast parameter coordination process.BS1 is the base station 50 of starting, and as the arbitrator.BS1 is represented by BS2 in Fig. 3, and its adjacent base station 50 sends BCMCS parameter coordination request (step a).BCMCS parameter coordination request message comprises BCMCS stream ID related with broadcasting stream and the sector ID that receives the sector of register requirement.BCMCS parameter coordination request message can comprise also that broadcast parameter that its suggestion is used is set and it will transfer the tabulation of it self soft handoff sectors of the soft handover of identification of broadcast stream to.BS2 is one of adjacent base station that receives BCMCS parameter coordination request message.BS2 adopts broadcasting coordinate responses message to respond (step b).BCMCS parameter coordination response message comprises the BCMCS stream ID of identification of broadcast stream.If the request base station broadcast parameter of advising can't be used in the response base station, then it can comprise in the broadcast parameter coordinate responses and replys the alternative set that the broadcast parameter of being willing to be intended to use on the boundary sector in base station 50 is set.Broadcast parameter coordinate responses message comprises that it will transfer the tabulation of the sector under the control of response base station 50 of soft handover to.Broadcast parameter coordinate responses message can comprise in certain embodiments and shows that broadcast parameter will be the operate time of effective time.After the information of all neighborhoods of hearing it, what broadcast parameter the base station 50 of starting determines to use set, and comprise by adjacent base station control, the sector that will use the identity set of public broadcasting parameter setting.Be used for determining that the decision algorithm of final broadcast parameter setting can be depending on ISP's target.For example, if ISP's main target is to make soft combination maximization, the transmission rate of maximum soft handover area can be selected to provide in the base station 50 of then starting.The base station 50 of starting sends BCMCS parameter coordinations to its adjacent base station 50 and transfers message, shows with the broadcast parameter setting that will use and is included in the relevant final decision (step c) in sector in the soft handover.Broadcast parameter is transferred and also can be comprised and show that broadcast parameter will be the operate time of effective time.If adjacent base station 50 need carry out such operation, then according to establishing good known procedure foundation and the (step d) that is connected of PDSN 22.In some cases, the base station 50 of starting may need to change its transmission parameter.This class changes the new (step e) that is connected of may require to start base station 50 requests and PDSN 22.

[0038] some scheduled broadcast is coordinated incident and can be triggered base station 50 initiation broadcast parameter coordination process, as mentioned above.The possible triggering of coordinating for broadcast parameter comprises:

● from the reception of the register requirement of travelling carriage 100.

● the variation of the condition of the needs of provisioning change BCMCS transmission rate.

● the beginning of BCMCS session.

● regular calibration changes.

● after the transmission of travelling carriage 100 is interrupted.

● whether travelling carriage 100 detections lack synchronously and ask base station 50 synchronous again.Whether travelling carriage 100 can detect according to the quantity of the frame erasing on the predetermined window and lack synchronously.If the quantity of frame erasing surpasses certain thresholding, then travelling carriage 100 can ask base station 50 to make broadcast parameter synchronous.

When the broadcast parameter coordination process was triggered, base station 50 adopted three-hand shake process and its soft handover neighborhood to consult broadcast parameter, as mentioned above.When handshake procedure was finished, each related base station 50 will know what broadcast parameter will use on which sector, and will have and will use the tabulation of other soft handoff sectors of identical broadcasts parameter.Soft handoff sectors can be transmitted to travelling carriage 100 in each base station 50 in the broadcast system parameter message tabulation.Then, travelling carriage 100 can determine which sector will be included in its active set when carrying out soft handover.

[0039] Fig. 4 explanation is configured to realize the exemplary base station 50 of above-mentioned broadcast parameter coordination process.Base station component in the example embodiment is distributed between RBS 46 and the BSC 44.The interface circuit 56 that RBS46 comprises RF circuit 52, baseband processing circuitry 54 and is used for communicating by letter with BSC 44.BSC 44 comprises the interface circuit 62 that is used for interface circuit 58, the communication control circuit 60 of communicating by letter with RBS 46 and is used for communicating by letter with PCF 42.Communication control circuit 60 comprises the broadcast service function 64 of the Processing tasks that execution is relevant with broadcast service and the provided for radio resources management circuit 66 of the management of base station 50 employed radio and the communication resource.Communication control circuit 60 can comprise one or more processors of the function that is programmed for executive communication control circuit 60.Broadcast service function 64 receives the GRE bag that transmits from PDSN 22, the GRE bag is unpacked, and will broadcast that stream format turns to frame so that send one or more travelling carriages 100 to by air interface.Broadcast service function 64 also is responsible for coordinating broadcast parameter with adjacent base station 50, as previously described.Broadcast service function 64 can realize in the processor that is programmed for the function of carrying out BSF 64.

[0040] Fig. 5 is a flow chart, and the demonstration programme 150 that is moved on the base station 50 of initiating broadcast parameter coordination process as shown in Figure 3 by broadcasting controlled function 64 is described.This process is taking place to begin (frame 152) when broadcast parameter is coordinated incident.Base station 50 can send broadcast parameter to its adjacent base station pre-configuredly and coordinate request message (frame 154), and waits for that predetermined period of time is to receive the response from adjacent base station 50.After receiving from each the broadcast parameter coordinate responses message in its neighborhood, perhaps through after the predetermined period of time, the base station 50 of starting determines that the broadcast parameter of soft handovers sets and soft handoff sectors (frame 158).Then, start base station 50 to its adjacent base station 50 transmission broadcast parameters transfer message, the sector (frame 160) that shows the broadcast parameter of being consulted and hand over to soft handover.In case of necessity, base station 50 is established to the connection of PDSN 22, if do not set up yet, then receives broadcasting stream (frame 162).The broadcast parameter that base station 50 adopts broadcast parameter to transfer appointment in the message is set the broadcasting stream (frame 164) that transmits in the sector that comprises in the soft handover tabulation.

[0041] Fig. 6 is a flow chart, and the demonstration programme 170 that is moved by broadcast service function 66 on the base station 50 that response broadcast parameter is as shown in Figure 3 coordinated to ask is described.Base station 50 receives from the broadcast parameter of adjacent base station 50 and coordinates request (step 172).The institute's broadcast parameter of advising setting and available sector (frame 174) are determined in base station 50, and return broadcast parameter coordinate responses message (frame 176).Then, base station waits is transferred message from the broadcast parameter of the base station 50 of starting.When receiving broadcast parameter coordination transfer message (frame 178), base station 50 is established to the connection of PDSN22, if set up yet, then receive broadcasting and flow (frame 180), and the broadcast parameter that adopts broadcast parameter to transfer appointment in the message is set the broadcasting stream (frame 182) that transmits in the transfer sector.

[0042] in an alternative of the present invention, principal and subordinate or centralized approach can be used for broadcast parameter to be coordinated.Principal and subordinate or centralized control method are distributed to maximum soft handover area (MSHOR) with each sector, and dominant base 50 is appointed as in a base station 50 among the MSHOR.A sector only can belong to a MSHOR.The dominant base 50 of MSHOR is according to determining broadcast parameter from the report of other base station 50 among the MSHOR.Dominant base 50 can adopt the three-hand shake process similar to reciprocity method to arbitrate the broadcast parameter coordination process.Sector among the MSHOR can dynamically be added and be deleted.For example, when travelling carriage 100 was registered in one of sector, perhaps when specific radio program began, to soft handover can be transferred one of its sector in the base station 50 among the MSHOR.When speed that dominant base 50 is set or other parameter were no longer supported in this sector, perhaps when not having the user to receive specific broadcasting stream in the sector, one of its sector can be deleted in base station 50 from the soft handover that dominant base 50 is controlled.Switch in the BSC less than remaining feasible between the sector of adding soft handover by dominant base 50 to.

[0043] Fig. 7 is a call flow diagram, and the broadcast parameter coordination process that switches between BSC according to another embodiment of the invention is described.The call flow diagram instruction card is shown three base stations 50 of dominant base, BS1 and BS2.In example shown in Figure 7, travelling carriage 100 has moved to the borderline region 44 of the sector in the area of coverage of BS1, and sends login request message to BS1, and its triggers broadcast parameter coordination process.BS1 sends BCMCS parameter coordination request message (step a) to dominant base.The broadcast parameter of advising setting that BCMCS parameter coordination request message comprises the BCMCS stream ID related with broadcasting stream, receives the sector ID of the sector of register requirement, its wishes to use and it will hand over to its tabulation of soft handoff sectors of soft handover.Dominant base 50 is known the current broadcast parameter related with broadcasting stream.In case of necessity, dominant base 50 can respond from the broadcast parameter of BS1 and coordinate to ask to change the broadcast parameter setting, perhaps can determine to continue to use current broadcast parameter to set.Dominant base 50 adopts broadcasting coordinate responses message to respond (step b).BCMCS parameter coordination response message comprises parameter operate time that the BCMCS of identification of broadcast stream flows the broadcast parameter setting of ID, broadcasting stream, transmits the tabulation of the soft handoff sectors of broadcasting stream and show the time of beginning applying broadcasting parameter setting.The base station BS 1 that starts sends the BCMCS parameter coordination to dominant base 50 and transfers message, shows that it will hand over to the sector (step c) of soft handover according to specified broadcast parameter in the broadcast parameter coordinate responses message.In case of necessity, 50 each base stations 50 in MSHOR of dominant base send broadcast parameter and coordinate request message (step d).For example changed in the situation of broadcast parameter setting at dominant base 50, this step may be necessary.Broadcast parameter is coordinated request message and is comprised that broadcasting stream ID, broadcast parameter are set, SHO tabulates and show that it will be the operate time of effective time that new broadcast parameter is set.Coordinate each base station 50 of request message from dominant base reception broadcast parameter and return broadcast parameter coordination transfer message, it comprises that BCMCS flows ID and it can coordinate the sector (step e) that new broadcast parameter setting specified in the request message hands over to soft handover according to broadcast parameter.

[0044] Fig. 8 illustrates the broadcast stream bag so that pass to a kind of demonstration methods of travelling carriage 100.The IP bag sends PDSN 22 to from BCMCS-CS 28.Framing function in the PPP layer on the PDSN 22 makes the IP packet framing, to produce the HDLC frame.Those skilled in the art can know, does not need the HDLC framing, and can be used as substituting or replenishing of HDLC framing on the PDSN 22 according to the broadcasting frame-forming protocol in the framing on the BSC.

[0045] PDSN 22 is divided into a plurality of sections with the HDLC frame, and these sections are inserted into the GRE frame so that send BSC 44 to via the A8/A10 interface.The GRE frame comprises GRE head and GRE payload.The GRE payload carries HDLC frame or frame section, and is divided into eight bit byte.In a preferred embodiment, the GRE payload comprises the header extension that wherein comprises markers, sequence number or other synchronizing information.The existence of header extension can by in the GRE head or the protocol type field in the A11 register requirement/response message when setting up A10 and connect represent.BSC 44 adopts the markers or the sequence number that comprise in the GRE header extension to determine by the time of air interface to travelling carriage 100 transmission PDU.Markers shows that the PDU of first eight bit byte that comprises the GRE bag sends the time of PDSN 22 to by the A8/A10 interface.

[0046] the 44 couples of GRE of BSC bag decapsulation, with the GRE payload mappings that deducts the GRE header extension to Packet Data Unit (PDU) so that send travelling carriage 100 to by air interface.Data from two or more GRE bags can be mapped to single PDU.Person of skill in the art will appreciate that first eight bit byte of GRE bag may not necessarily be positioned at the beginning of PDU.In some embodiments of the invention, the PDU that comprises last eight bit byte of GRE bag can adopt pseudo-position or filler to fill, and makes that first eight bit byte in each GRE bag is consistent with the beginning of PDU.But in the embodiment shown in fig. 6, when arriving last eight bit byte of GRE bag, BSC 44 begins to adopt the remainder of filling PDU from the data of next GRE bag.See that in Fig. 6 GRE bag is filled the part of preceding two PDU and the 3rd PDU.Be used for filling the remainder of the 3rd PDU from the position of the 2nd GRE bag.The the 4th and the 5th PDU comprises the user bit from the 2nd GRE bag.Each PDU comprises the broadcast frame that sends travelling carriage 100 by air interface to.

[0047] Fig. 9 illustrates data and the signaling paths in the example embodiment of the present invention, and it extremely is fit to the distributed control method of the coordination of broadcasting stream.Solid line among Fig. 9 represents to broadcast the path of stream, and dotted line then represents to broadcast the signaling paths of the relevant signaling of stream.In the embodiment shown in fig. 9, each base station 50 receives the identical broadcasts stream from PDSN 22.Other guy chain road between the BSC 44 is used for signaling between BSC.In the cdma200 network, the A7 interface comprises the other guy chain road that is used for signaling between BSC.An advantage of this method is that transmitting user data between BSC 44 does not need other guy chain road.But, need certain mechanism to make broadcast frame pass through to arrive the transmitting synchronous of travelling carriage 100 in the air.Above-described broadcast parameter coordination process can be used to coordinate the transmission of the broadcasting stream in the different sectors.As previously described, PDSN 22 can insert time synchronization information the GRE bag that passes to BSC 44, and they can be used to make broadcasting stream time synchronized in conjunction with the additional period synchronization parameter by the exchange of other guy chain road by BSC 44.The demonstration methods of time synchronized is described below.

[0048] Figure 10 illustrates data and the signaling paths in another example embodiment of the present invention.In the embodiment shown in fig. 10, source base station 50 receives the broadcasting stream from PDSN 22, and is responsible for the living broadcast frame that transmits by air interface of specific broadcasting miscarriage.During soft handover, source base station 50 transmits broadcasting stream by other base station 50 of other guy chain road direction.When the base station 50 outside source base station 50 received from the register requirement of travelling carriage 100, flowed to source base station 50 request contents base station 50, and receive broadcasting stream by other guy chain road.

[0049] Figure 11 is a call flow diagram, and the demonstration program that is used for broadcasting to source base station 50 requests stream by base station 50 is described.The request base station is when the register requirement that receives from travelling carriage 100, send BCMCS parameter coordination request (step a) to all adjacent base stations 50 that comprise source base station, and receive BCMCS parameter coordination response (step b and c) from each adjacent base station, as the front described in Fig. 3 and shown in.According to the response from adjacent base station 50, request base station 50 definite broadcast parameters that will use are set and soft handoff sectors, as previously described.Register requirement identification sources base station 50 from travelling carriage 100.50 of base stations of request send the BCMCS content request message to source base station 50, so that request broadcasting stream (step d).The BCMCS content request message comprises the BCMCS stream ID and the broadcast parameter setting of broadcasting stream.Source base station 50 returns BCMCS content response message (step e) to request base station 50.BCMCS content response message comprise BCMCS stream ID and operate time parameter.Operate time, parameter showed that to request base station 50 source base station 50 will begin the time of transmitting broadcasting stream by other guy chain road direction request base station 50.If source base station 50 does not have the broadcasted content of the parameter setting of appointment in the BCMCS content requests, then source base station 50 has the content that correct broadcast parameter is set to PDSN 22 requests.Then, request base station 50 sends the BCMCS broadcast parameter to the adjacent base station 50 that comprises source base station 50 and transfers (step f).

[0050] be connected among the embodiment of identical PDSN 22 or BSN 24 in all base stations 50, the markers method can be used for making the transmitting synchronous of broadcasting stream by the BSC border.To adopt Fig. 8 to describe a kind of demonstration markers method as reference.When BCMCS transmission beginning, base station 50 is according to the markers in the GRE bag and show the expection time offset T of bag stand-by period _BiasingCalculate the time of the transmission of the stream of going on the air.Time offset can be pre-configured, and a part that perhaps can be used as foregoing broadcast parameter negotiations process is held consultation.Markers can be inserted the GRE bag by PDSN 22 or BSN 24.Markers can show that the PDSN 22 of BSN 24 transmits the time of GRE bag or the time that draws from packet transmission time.Perhaps, the markers in the GRE bag can be from drawing from the markers of the RTP bag that content server 28 is received on PDSN 22 or the BSN 24.

[0051] base station 50 according to following formula calculate first broadcast frame of a part that comprises GRE bag GRE (i) among the s of sector original transmission zero-time TBS (i, s):

TBS (i, s)=TCN (i)+T _BiasingEquation (1)

Wherein, i is the sequence number of GRE bag, and TCN (i) is that PDSN 22 transmits the time of GRE bag or other time scale value by the A8/A10 interface, and T _BiasingIt is time offset.If (i, calculated value s) are not possible frame zero-times to TBS, and then (i is next frame transmission start time by round-up s) to TBS.Equation 1 also is used in after the transmission interruption or response is carried out synchronous from the synchronization request again of travelling carriage again.

[0052] for be expressed as GRE (j) (the follow-up GRE bag of j＞i) wherein, BSC 44 can according to following formula calculate the primary frame that comprises GRE (j) frame transmission start time TBS (j, s):

Equation (2)

TBS (i wherein, s) be the frame transmission start time of first broadcast frame that comprises the part of GRE (i), TBS (j, s) be the frame transmission start time of first broadcast frame that comprises the part of GRE (j), (i s) is the primary position of the GRE (i) in the initial frame to P, and N (k) is the quantity that has the user bit of sequence number k in the GRE bag, S is the quantity of the user bit in the broadcast frame, and Δ t is the broadcast frame transmission time.Summation in the equation 2 provides the sum that begins the user bit in the previous GRE bag of all of GRE (j-1) with GRE (i).Variable P (i, s) figure place in the frame before first user bit of explanation GRE (i).The total bit that is transmitted is divided by the figure place among the frame S, thereby obtains the frame number that transmitted, and it is immediate integer value by round down.The quantity of broadcast frame and frame transmission time multiply each other, thereby obtain the overall transmission time of each whole frame, have wherein ignored the user bit among the GRE (j) that changes last frame over to.Overall transmission time add first frame of a part that comprises GRE (i) frame transmission start time TBS (i, s), thereby obtain comprising GRE (j) a part first frame frame transmission start time TBS (j, s).

[0053] GRE (i _n) in primary original position P (i _n, s) can calculate according to following formula:

$P(j,s)=(P(i,s)+\underset{k=i}{\overset{j-1}{\mathrm{\Σ}}}N\left(k\right))\mathrm{mod}S$ Equation (3)

Equation 3 calculate the user bit that transmits in GRE (j) all frames before that the initial frame with GRE (i) begins with mould S.This sum comprises first position before of the GRE (i) in the initial frame.

[0054] when the 50 beginnings broadcasting that transmission has been transmitted in adjacent sectors s ' by second base station 50 in the s of sector of first base station is flowed, in order to obtain the frame transmission start time TBS (i of the current GRE frame GRE (i) that is transmitted, s ') and original position P (i, s '), first base station 50 that is expressed as BS1 can be asked to second base station, 50 transmissions that are expressed as BS2.When 1 wait acknowledge of first base station BS, it can calculate each the quantity of the user bit in the GRE that the transmits bag, make its calculate the frame transmission start time TBS of frame (j, s) and original position P (j, s), so that make the transmission among the s ' of sector synchronous with transmission sector s.That is to say that base station BS 1 will calculate

Wait for BS2 report frame transmission start time TBS (i, s ') and original position P (i, s ') simultaneously.Then, BS1 be provided with TBS (j, s)=TBS (j, s ') and P (j, s)=P (j, s ').Broadcast parameter coordination process shown in Figure 3 can be used to synchronization parameter swap time.

[0055] if broadcast channel is inserted with signaling in base station 50, make to postpone transmission from the user data that PDSN received, but then application class like calculating, as long as above-mentioned delay equates on all base stations 50 of transmitting broadcasting stream to travelling carriage 100.Signaling message for not sending in all sectors can adopt foregoing broadcast parameter coordination process to delete the sector from soft handover, after signaling is finished these sectors is added soft handover again then.

[0056] send the difference of user data because signaling message is inserted into broadcasting stream and PDSN 22 to base station 50, the latency time period possibility that in fact time that PDSN 22 sends user data and user data be sent between time of travelling carriage 100 is different.This species diversity will make the buffer level on the base station 50 change and increase and reduce along with the bag stand-by period again.If PDSN 22 surpasses the Mean Speed of base station 50 to travelling carriage 100 transmission data to the Mean Speed that base station 50 sends user data, then the filling grade of buffer will increase, and may cause buffer to overflow.On the contrary, if PDSN sends Mean Speed from user data to base station 50 sends the Mean Speed of user data less than base station 50 to travelling carriage 100, then buffer level will reduce, and may to cause buffer be empty, that is, and and buffer underflow.In order to prevent that buffer from overflowing/underflow, can be buffer level triggering synchronous again upper and lower bound automatically is set.Upper and lower bound can be pre-configured by Virtual network operator, perhaps can consult between base station 50 in the described in front broadcast parameter coordination process.

[0057] in one embodiment of the invention, by elapsed time between the frame transmission start time of calculating PDSN 22 transmits time from the GRE bag to base station 50 and the initial broadcast frame of a part that comprises the GRE bag, calculate and wrap stand-by period L.The time that PDSN 22 transmits the GRE bag is identified by the markers TCN (i) in the GRE bag.(i s) can calculate according to equation 2 or other Time Calculation algorithm frame transmission start time TBS.Base station 50 is transmitted the time of GRE bag and the stand-by period L between the frame transmission start time according to following formula monitoring PDSN 22 to base station 50:

L=TCN (i)-TBS (i, s) equation (4)

If bag stand-by period L surpasses upper limit L _{The upper limit}, then base station 50 abandons selected GRE bag and overflows so that prevent buffer.If bag stand-by period L is less than lower limit, base station 50 infilled frames or send empty frame then are so that increase the bag stand-by period.Frame also can be distributed to another user in base station 50.Each method in these methods is created the gap in the transmission of broadcast frame, so that allow the time fill buffer.Under any situation, all trigger automatically synchronizing process again.

[0058] under the situation that buffer overflows, the GRE bag is dropped from the buffer afterbody, reduces to greater than T up to estimated wait time _BiasingMinimum value.If j represent to trigger buffer overflow (TBS (and j, s)-TCN (j)＞L _{The upper limit}) GRE bag, the GRE that is then abandoned bag will be the bag that meets the following conditions:

TBS (i, s)-TCN (i)≤L _{The upper limit}Equation (5)

TBS (i, s)-TCN (j)＞T _BiasingEquation (6)

First condition guarantee to trigger automatically again synchronizing process bag, be that GRE (j) is retained.Second condition selects the markers TCN (j) of GRE (j) that its planned transmission zero-time surpasses them more than T _BiasingGRE (j) all GRE bag before.The frame transmission start time of the initial frame of GRE (j) is recomputated in base station 50.If k is the sequence number of last GRE bag of not abandoning, then the transmission start time of GRE (j) can be calculated according to following formula:

Equation (7)

The original position of GRE in the initial frame (j) can be calculated according to following formula:

P (j, s)=(P (k, s)+N (k)) mod S equation (8)

Therefore, GRE (j) will be transmitted afterwards immediately at GRE (k).

[0059] the automatic example of synchronizing process again of following table 1 explanation.

Table 1-buffer overflows example
									i	T	TCN(i)	N(i)	P(i，s)	TBS(i，s)	L(i，s)		The buffer top filling
0	0	0	12384	0	800	800		12384
									1	100	100	12384	864	980	880		24768
2	110	110	320	448	1180	1070		25088
									3	200	200	12384	768	1180	980		37472
4	310	310	12384	352	1380	1070		49856
									5	380	380	12384	1216	1560	1180		62240
6	445	445	12392	800	1760	1315		74632
									7	500	500	9600	392	1960	1460		84232
8	600	600	12384	1032	2100	1500		96616
									9	700	700	12384	616	2300	1600	Discarded packets	109000
10	750	750	12384	200	2500	1750	121384
								11	800	800	12384	1064	2680	1880	133768
12	960	960	12384	648	2880	1920	133768
								13	1100	1200	4320	232	3080	1880	125384
14	1250	1250	12112	712	3140	1890	125112
								15	1400	1400	12384	24	3340	1940			137496
1400	1400	12384	616	2300	900	The value that recomputates	71528

[0060] in the example shown in the table 1, first time 0 that wraps in shown in markers TCN (0) is transmitted to base station 50, and is equaling T _BiasingTime 800 be transmitted.The GRE bag GRE (0) that comprises 12384 is placed into the transmission buffer, therein, it remain to given transmission time T BS (0, s) (it equals 800 in this example).Note, and the original position P of GRE (0) (0, S) equal 0, because the transmission of GRE bag is consistent with the beginning of frame.Second bag GRE (1) was received in the time 100, and was placed into the transmission buffer.Base station 50 according to equation 2 calculate the primary frame that comprises GRE (1) transmission start time TBS (1, s).Second bag comprises 12384 user bit, and they need 864 of nine whole frame and the tenth frame to transmit.Multiply each other for the frame transmission time of 20ms in the quantity of whole frame and this example, and the result is added the frame transmission start time TBS (0 of the primary frame that comprises GRE (0), s), thus obtain comprising the primary frame of GRE (1) frame transmission start time TBS (1, s).In this case, and frame transmission start time TBS (1, s) be calculated as 980.The bag stand-by period has been increased to 880, and buffer level has been increased to 24768.After the 15th GRE bag GRE (14) transmitted by PDSN, the bag stand-by period had been increased to 1890, and buffer level has been increased to 125112.When receiving the 16th GRE bag GRE (15), and bag stand-by period L (15, s) be increased to 1940, it is greater than maximum bag stand-by period L _{The upper limit}(being set to 1900 in this example), thus synchronizing process again triggered automatically.Trigger synchronous more automatically bag the time be designated as 1400.Note, and TBS (8, s)＞TCN (15)+T _Biasing, and TBS (9, s)＞TCN (15)+T _BiasingTherefore, transmit GRE (15) afterwards immediately, and choose tundish GRE (9)-GRE (14) and be used for deleting from buffer at GRE (8).Observe to delete to wrap and satisfy equation 5 and 6.At deletion bag GRE (9)-GRE (14) afterwards, the frame transmission start time TBS of bag GRE (15) (15, s), original position P (15, s) and bag stand-by period L (15, s) according to TBS (8, s), P (8, s) and N (8) recomputate.The synchronization parameter that recomputates of GRE (15) be TBS (15, s)=616, P (15, s)=2300, they equal the relevant parameter of GRE (9) because these CALCULATION OF PARAMETERS also based on TBS (8, s), P (8, s) and N (8), and L (15, s)=900.

[0061] under the situation of buffer underflow, base station 50 postpones the transmission of GRE bag, and adopts pseudo-position or filler to fill any insertion frame.If j is the sequence number that triggers the GRE bag of underflow condition, then the frame transmission start time TBS of GRE (j) (j, s) and original position P (j, s) reset in such a way:

TBS (j, s)=TCN (j)+T _BiasingEquation (9)

P (j, s)=0 equation (10)

If (j s) is not possible frame zero-time to TBS, and then (j is next possible frame transmission start time by round-up s) to TBS.Queuing GRE bag is mapped to air interface frame usually.When having transmitted before all GRE bags of GRE (j), (j s) is inserted into the air interface frame that has transmitted before at TBS in pseudo-position.

[0062] following table 2 explanation buffer underflow situations.

Table 2-buffer underflow example
										c	T	TCN(i)	N(i)		P(i，s)	TBS(i，s)	L(I，s)		Buffer is filled lower limit
0	0	0	1350	10800	0	800	800		0
										1	200	200	1200	9600	560	960	760		0
2	400	400	1100	8800	1200	1100	700		10800
										3	500	500	680	5440	1040	1240	740		10800
4	600	600	760	6080	1040	1340	740		20400
										5	800	800	1200	9600	720	1440	640		18400
6	1000	1000	1400	11200	80	1600	600		20320
										7	1200	1000	1200	9600	1040	1760	760		21120
8	1400	1400	996	7968	400	1920	520		20800
										8	1600	1600	880	7040	688	2040	440		20800
9	1800	1800	798	6384	48	2160	360	Fill	7968
										1800	1800	798	6384	0	2600	800	The value that recomputates	7968
	10	2000	2000	1230	9840	1264	2680	680	7040
11										2200	2200	1002	8016	864	2840	640		6384
	12	2400	2400	1548	12384	1200	2960	560	16224
13										2600	2600	1440	11520	784	3160	560		24240

[0063] as shown in table 2, the bag stand-by period of GRE (9) drops to be lower than and is minimum threshold L _{Lower limit}400.Bag GRE (9) comprises and equals 1800 markers.Base station 50 is with T _BiasingScale value recomputates the frame transmission start time of GRE (9) when adding, thereby obtains new frame transmission start time 2600, and it is consistent with the beginning of frame in this example.If the beginning of new frame transmission start time and frame is inconsistent, then new frame transmission start time will be next possible frame transmission start time by round-up.Base station 50 with original position P (9, s) be set to zero, because first of GRE (9) will be consistent with first of air frame.

[0064] base station also can come the time of implementation synchronous according to the sequence number of being put into the GRE bag by PDSN 22 or BSN 24.For synchronous according to the sequence number time of implementation, base station 50 can adopt above-mentioned broadcast parameter coordination process consult to have the frame transmission start time TBS of the bag of sequence number i (i, s).Then, can come the frame transmission start time and the original position of calculated for subsequent GRE bag according to above equation 2 and 3.Can be regular more synchronously.

[0065] during move operation, may wish to allow base station 50 in broadcasting stream, to send the 3rd layer of (L3) signaling message to travelling carriage 100.For example, base station 50 may wish to send broadcast system parameter message or other Overhead Message to the travelling carriage 100 of monitoring broadcast channel.A kind of method that realizes the broadcasting of the Overhead Message on the broadcast channel is temporarily to abandon wherein those sectors of broadcast overhead messages from soft handover, and after signaling is finished the sector is added soft handover again.This method is complicated, and requires the coordination between participation base station 50 and the travelling carriage 100.For example, soft handover branches is dropped and time of adding need and receive between the travelling carriage 100 of broadcasting stream in base station 50 and coordinate.This coordination need be by participating in the other guy chain road between the base station 50 signaling and travelling carriage 100 and participation base station 50 in one or more between aerial signaling.This method may cause performance degradation in those cycles that soft handover branches is dropped.Because the duration of signaling message is extremely short usually, therefore this method may not be that Virtual network operator is wished.

[0066] the another kind of method of the signaling on the realization broadcast channel is cancellation or the frame that postpones to be intended for use in sending to the travelling carriage 100 in all related sectors of soft handover.Signaling message can be inserted into by cancellation or postpone to carry the frame of broadcasting stream and become in the available frame.In this method, need send a notification message to adjacent base station by the base station 50 that broadcast channel sends signaling or Overhead Message.Notification message comprises that it will begin to transmit the duration of the transmission of the size of the time of Overhead Message, Overhead Message and Overhead Message.Notification message can send its soft handover neighborhood to from the base station 50 of initiating signaling by other guy chain road.Message can comprise field operate time, length field and optional message field.Operate time, field comprised the time that the base station 50 of starting will begin to transmit by broadcast channel signaling message.Length field shows the length of signaling message, and it can be used for determining the duration of signaling message by other base station 50.Optional message field can comprise the signaling message that sends travelling carriage 100 to.Notification message is used to make to the transmission of the stream of the broadcasting after the transmission of the Overhead Message of travelling carriage synchronous again.

[0067] when starting base station 50 when its soft handover neighborhood provides signaling message, may require the soft handover neighborhood to transmit signaling message to travelling carriage 100, thus the soft combination of the signaling message that permission travelling carriage 100 carries out.Base station 50 does not provide signaling message if start, and then the soft handover neighborhood must enter discontinuousness transmission mode, and stops transmission in the duration of signaling message.When enabling the Reed-Solomon coding, may not use discontinuous transmission, because the parity check bit that outside Reed-Solomon coding is produced will not match, thereby cause losing of whole Reed-Solomon piece.For fear of enabling Reed-Solomon this problem in when coding, the signal message by broadcast channels carry common need transmit in all sectors.

[0068] when the bandwidth of broadcast channel flowed required bandwidth greater than support broadcasting, a plurality of broadcasting streams can be multiplexed on the identical broadcast channel.In order to realize the borderline soft combination of BSC, the frame that is transmitted need be all identical in all sectors.If the frame that transmits by broadcast channel comprises the data that flow from a plurality of broadcasting, then given base station 50 may need to subscribe current unwanted broadcasting stream, and is identical to support soft combination because all frames all need.

[0069] the invention provides the support of flowing, unnecessarily subscribe broadcasting stream and need not base station 50 for the multiplexing broadcast on the same broadcast channel.Base station 50 can be divided into broadcast channel a plurality of time slots, and identifies the broadcasting stream that carries in each time slot.Like this, travelling carriage 100 can carry out soft combination to those time slots that broadcasting stream is paid close attention in carrying.The base station 50 that participates in soft handover can adopt above-mentioned broadcast parameter coordination process to consult which time slot to be used for given broadcasting stream.All the other time slots can be used to transmit other broadcasting stream, and perhaps base station 50 can discontinuousness transmission mode work, and stop transmission in not with time slot.Do not need base station 50 for the current broadcasting stream of one of its sector that do not need.Different broadcasting stream can be transmitted in different base stations in identical time slot, short of travelling carriage carries out soft combination with time slot and various flows.Therefore, multiplexing broadcast stream may be different in different sectors.

[0070] when multiplexing a plurality of broadcasting were flowed in a frame on the broadcast channel, the bandwidth of broadcast channel must equal the summation of the required bandwidth of each broadcasting stream at least.The required bandwidth B of N broadcasting stream is expressed as:

${\mathrm{\Σ}}_{i=1}^N{B}_i$ Formula (11)

Wherein, B _i≤ B, and B _iRepresent with kbs.Some broadcasting streams may need whole time slot, and other broadcasting stream then can be grouped into single time slot.If some broadcasting streams can be through combination, making needs M＜N time slot, and then formula 11 can be write:

${\mathrm{\Σ}}_{i=1}^M{B}_i$ Formula (12)

[0071] in one embodiment of the invention, time slot is 20ms.If the frame sign on the BCH is the multiple of 20ms normally, then each frame on the BCH can be divided into the 20ms time slot equably.If T is expressed as the time cycle that all broadcasting streams provide the bandwidth requirement of service to satisfy each broadcasting stream.T can be expressed as the quantity of 20 milliseconds of time slots.The value of T is determined respectively to broadcast periodicity and the required buffer sizes of support multiplexing broadcast stream that stream provides service with thinking.

[0072] difficult problem is to determine that optimal service is in the required minimum time period T of all multiplexing broadcast streams.The MINIMUM BROADCASTING interval T can be calculated according to following formula:

$T_{\mathrm{MIN}}=\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\frac{B_i}{\mathrm{GCF}}$ Equation (13)

In equation 13, the bandwidth B of each broadcasting stream _iDivided by the greatest common factor (G.C.F.) GCF of all broadcasting streams, and to result's summation, thereby draw the MINIMUM BROADCASTING interval T _MINIn this calculating, two or more broadcasting streams of shared identical time slot are used as single broadcast stream and handle.By making broadcast interval is minimum, and the size that makes the de-jitter buffer on the travelling carriage is for minimum.

[0073], supposes that base station 50 is multiplexed into three broadcasting streams on the BCH with the data rate of 10kbs, 12kbs and 20kbs respectively as an example.The greatest common factor (G.C.F.) of these three broadcasting streams is 2000.Therefore, MINIMUM BROADCASTING interval T _MINCan calculate according to following formula:

$T_{\mathrm{MIN}}=\mathrm{\Σ}\frac{\mathrm{10,000}}{\mathrm{2,000}}+\frac{\mathrm{12,000}}{2.000}+\frac{\mathrm{20,000}}{\mathrm{2,000}}$ Equation (14)

T _MIN＝∑5+6+10

T _MIN＝21

In this example, broadcast interval T _MINEqual 21 frames.T _MINThe value and the starting point of time slot allocation and broadcast interval need be delivered to other base station 50 that participates in soft handover.

[0074] under any circumstance, it will be understood by those of skill in the art that the present invention is not limited by the argumentation of front, is not subjected to the restriction of accompanying drawing yet.On the contrary, the present invention is only limited by following claim and suitable legal equivalents thereof.

Claims (32)

1. transmission synchronizing method that during soft handover, makes broadcasting stream from a plurality of base stations to travelling carriage, described method comprises:

Receive the employing markers in the base station and carry out the packet of mark;

Calculate the frame transmission start time of the start frame that is used for each packet according to the markers in each packet; And

According to the frame transmission start time of being calculated that is used for each packet, make the transmitting synchronous of packet from described base station to travelling carriage.

2. the method for claim 1 is characterized in that, the packet markers is to be applied at service node by the grouped data that broadcasting stream is provided to described base station.

3. the method for claim 1 is characterized in that, the packet markers is to draw in the time that service node sends packet from grouped data.

4. method as claimed in claim 3 is characterized in that, the packet markers be from be derived from from the RTP bag that content server receives the time target time draw.

5. the method for claim 1 is characterized in that, the frame transmission start time of calculating the start frame that is used for each packet comprises:

The transmission time of calculated data bag adds any position that changes over to from previous packet;

Calculating transmission time is added the frame transmission start time of previous packet, transmit initial thereby draw the frame that is used for next packet.

6. method as claimed in claim 5 is characterized in that, the transmission time of calculated data bag adds that any position that changes over to from previous packet comprises:

Calculate transfer data packets and change a quantity of required whole frame over to; And

Calculating is used for the transmission time of the whole frame of the quantity calculated.

7. method as claimed in claim 6 is characterized in that, also comprises the original position of each packet that calculates the start bit position that shows the start frame that is used for packet.

8. the method for claim 1 is characterized in that, also comprises according to the markers that comprises in the packet calculating the bag stand-by period that is used for each packet.

9. method as claimed in claim 8 is characterized in that, calculates the bag stand-by period be used for each packet to comprise poor between the frame transmission start time of calculating the start frame that is used for packet and the markers.

10. method as claimed in claim 8 is characterized in that, also comprises the bag stand-by period and the predetermined maximum latency of each packet of comparison, and if wrap the stand-by period above predetermined maximum latency, then synchronous again.

11. method as claimed in claim 10 is characterized in that, comprising synchronously postpones again abandons the selected data bag in device, and recomputates the described packet discard frame transmission start time of any packet in described buffer afterwards.

12. method as claimed in claim 8 is characterized in that, also comprises the bag stand-by period and the predetermined minimum latency of each packet of comparison, and if wrap the stand-by period less than predetermined minimum latency, then synchronous again.

13. method as claimed in claim 10 is characterized in that, comprises the frame transmission start time that postpones the selected data bag more synchronously, so that create the gap in the transmission of broadcasting stream.

14. method as claimed in claim 13 is characterized in that, also comprises adopting pseudo-position to fill institute's deferred frame one or more frames before.

15. method as claimed in claim 14 is characterized in that, transmits empty frame during also being included in the described gap in the described broadcasting stream.

16. method as claimed in claim 14 is characterized in that, also comprises the frame in the described gap is redistributed to another user.

17. a base station controller comprises one or more control circuits, is configured to:

Receive and adopt markers to carry out the packet of mark;

Calculate the frame transmission start time of the start frame that is used for each packet according to the markers in each packet;

According to the frame transmission start time of being calculated that is used for each packet, make transmission and other base station synchronization of packet.

18. base station controller as claimed in claim 17 is characterized in that, the packet markers is to be applied at service node by the grouped data that broadcasting stream is provided to described base station.

19. base station controller as claimed in claim 18 is characterized in that, the packet markers is to draw in the time that service node sends packet from grouped data.

20. base station controller as claimed in claim 18 is characterized in that, the packet markers be from be derived from from the RTP bag that content server receives the time target time draw.

21. base station controller as claimed in claim 17 is characterized in that, base station controller calculates the frame transmission start time of the start frame that is used for each packet by following steps:

The transmission time of calculated data bag adds any position that changes over to from previous packet;

The transmission time of being calculated is added the frame transmission start time of previous packet, thereby the frame transmission that draws next packet is initial.

22. base station controller as claimed in claim 21 is characterized in that, base station controller comes the transmission time of calculated data bag to add any position that changes over to from previous packet by following steps:

Calculate transfer data packets and change a quantity of required whole frame over to; And

Calculating is used for the transmission time of the whole frame of the quantity calculated.

23. base station controller as claimed in claim 17 is characterized in that, base station controller also calculates the original position of each packet of the start bit position that shows the start frame that is used for packet.

24. base station controller as claimed in claim 17 is characterized in that, base station controller also calculates the bag stand-by period that is used for each packet according to the markers that comprises in the packet.

25. base station controller as claimed in claim 24 is characterized in that, base station controller is used for the frame transmission start time and the difference between the markers of the start frame of packet and calculates the bag stand-by period that is used for each packet by calculating.

26. base station controller as claimed in claim 24 is characterized in that, base station controller is the bag stand-by period and the predetermined maximum latency of each packet relatively, and if wrap the stand-by period above predetermined maximum latency, then synchronous again.

27. base station controller as claimed in claim 26, it is characterized in that base station controller comes synchronous by the frame transmission start time that abandons the selected data bag and recomputate any packet in described buffer after the described packet discard from buffer again.

28. base station controller as claimed in claim 24 is characterized in that, base station controller is the bag stand-by period and the predetermined minimum latency of each packet relatively, and if wrap the stand-by period less than predetermined minimum latency, then synchronous again.

29. base station controller as claimed in claim 28 is characterized in that, base station controller comes synchronous by the frame transmission start time that postpones the selected data bag again.

30. base station controller as claimed in claim 29, its feature are that also base station controller adopts pseudo-position to fill institute's deferred frame one or more frames before.

31. base station controller as claimed in claim 29 is characterized in that, base station controller transmits empty frame during the described gap in described broadcasting stream.

32. base station controller as claimed in claim 29 is characterized in that, base station controller redistributes the frame in the described gap to another user.

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